The Lorentz Force Law
Defining the magnetic field B via the force on a moving charge and the nature of currents.
Magnetostatics
While electrostatics deals with stationary charges, Magnetostatics deals with stationary
currents (steady flow of charge).
Here, the electric field is constant, but the moving charges generate a Magnetic Field (B).
The fundamental laws governing this regime are the Biot-Savart Law (analogous to Coulomb's
Law) and Ampère's Law (analogous to Gauss's Law). We also introduce the Vector Potential
A, which plays a mathematical role similar to the scalar potential V.
The Biot-Savart Law
Calculating the magnetic field produced by steady line, surface, and volume currents.
The Divergence and Curl of B
Ampère's Law, the absence of magnetic monopoles, and applications to symmetric systems.
Magnetic Vector Potential
Introducing the vector potential A, gauge freedom, and the multipole expansion.